Q: Which equation best represents the action of the Na\^+/K\^+ ATPase pump in the renal tubular cell?

$$3\ \mathrm{Na}^+_{\text{in}} + 2\ \mathrm{K}^+_{\text{out}} + \mathrm{ATP} \rightarrow 3\ \mathrm{Na}^+_{\text{out}} + 2\ \mathrm{K}^+_{\text{in}} + \mathrm{ADP} + \mathrm{P}_i$$

Question 1

Which of the following best describes the primary effect of aldosterone on renal function?

Accepted Answer

It increases sodium reabsorption and potassium secretion in the distal tubules and collecting ducts.

Question 2

A patient presents with dehydration due to severe diarrhea. According to the volume/osmolarity chart, what change occurs in the body?

Accepted Answer

Volume decreases and osmolarity increases.

Question 3

Which hormone is secreted in response to increased atrial wall stretch and promotes sodium and water excretion?

Accepted Answer

Atrial natriuretic peptide (ANP)

Question 4

What is the main driving force for sodium reabsorption in the proximal tubule?

Accepted Answer

Na\'/K\^+ pump on the basolateral membrane

Question 5

Which of the following scenarios would most likely trigger the release of renin from the juxtaglomerular cells?

Accepted Answer

A decrease in blood pressure detected by the afferent arteriole

Question 6

If a person ingests a large amount of isotonic saline, what is the expected effect on body fluid compartments?

Accepted Answer

Increase in extracellular fluid volume with no change in osmolarity

Question 7

Which of the following best explains why aldosterone cannot increase sodium reabsorption without also affecting potassium secretion?

Accepted Answer

Aldosterone stimulates the synthesis of proteins that increase both Na\^+ reabsorption and K\^+ secretion in the same cells.

Question 8

Which of the following is a direct effect of atrial natriuretic peptide (ANP) on the kidney?

Accepted Answer

Increased glomerular filtration rate (GFR) and decreased sodium reabsorption

Question 9

A patient has a plasma sodium concentration of 120 mEq/L (normal: 135-145 mEq/L). Which term best describes this condition?

Accepted Answer

Hyponatremia

Question 10

Which of the following best describes the fate of glucose filtered at the glomerulus under normal physiological conditions?

Accepted Answer

It is almost completely reabsorbed in the proximal tubule.

Question 11

Which equation best represents the action of the Na\^+/K\^+ ATPase pump in the renal tubular cell?

Accepted Answer

$$3\ \mathrm{Na}^+_{	ext{in}} + 2\ \mathrm{K}^+_{	ext{out}} + \mathrm{ATP} ightarrow 3\ \mathrm{Na}^+_{	ext{out}} + 2\ \mathrm{K}^+_{	ext{in}} + \mathrm{ADP} + \mathrm{P}_i$$

Question 12

Which of the following would most likely result in an increase in aldosterone secretion?

Accepted Answer

A decrease in blood pressure and an increase in plasma potassium

Question 13

A patient eats a large amount of salt without drinking water. According to the volume/osmolarity chart, what is the expected effect?

Accepted Answer

No change in volume, increase in osmolarity

Question 14

Which of the following is true regarding sodium reabsorption in the nephron?

Accepted Answer

About 70% of filtered sodium is reabsorbed in the proximal tubule, and this process is unregulated.

Question 15

Which hormone acts to decrease both sodium reabsorption and renin secretion in the kidney?

Accepted Answer

Atrial natriuretic peptide (ANP)

Question 16

A patient with heart failure has increased plasma volume and atrial stretch. Which hormone is likely to be elevated and what is its effect?

Accepted Answer

Atrial natriuretic peptide (ANP); increased sodium and water excretion

Question 17

Which of the following best describes the sequence of events in the renin-angiotensin-aldosterone system (RAAS) following a drop in blood pressure?

Accepted Answer

Renin release → angiotensinogen conversion to angiotensin I → ACE converts angiotensin I to angiotensin II → aldosterone secretion

Question 18

Which of the following substances is almost completely reabsorbed in the nephron under normal conditions?

Accepted Answer

Glucose

Question 19

A patient with hyperaldosteronism is likely to develop which of the following electrolyte imbalances?

Accepted Answer

Hypernatremia and hypokalemia

Question 20

Which of the following best explains why ANP secretion increases in response to increased plasma volume?

Accepted Answer

Increased atrial stretch stimulates ANP release to promote natriuresis and diuresis.

Chapter 20 B:Fluid, Electrolyte, and Acid-Base Balance: Sodium Regulation and Hormonal Control

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